Abstract

ABSTRACT:The inhaled β2-adrenergic agonists form the mainstay of therapy for mild to moderate asthma. They are also highly effective for the management of exercise-induced asthma and nocturnal symptoms of the disease. Mounting evidence suggests that these agents may have the potential for the development of tolerance, particularly to their bronchodilating effects, and this tolerance may be associated with increases in asthma-related morbidity and mortality, though this link remains controversial. However, experience to date indicates that the β-agonists do not share the same propensity to cause tolerance. Instead, tolerance appears to be more closely associated with the regular use of these drugs rather than their PRN use. Furthermore, clinically relevant tolerance is more likely in patients who are treated regularly with high doses of a bronchodilator for long periods. Current therapeutic recommendations suggest that inhaled β-agonists should be used on a PRN basis when possible and that the lowest effective doses should be administered.